Packaged semiconductor device with a reflow wall

Abstract

A packaged semiconductor device includes a lead frame and a semiconductor device. A solder joint is coupled between the lead frame and a terminal on the semiconductor device. A reflow wall is on a portion of the lead frame and is in contact with the solder joint. A molding compound covers portions of the semiconductor device, the lead frame, the solder joint, and the reflow wall.

What is claimed is: 
     
       1. A packaged semiconductor device comprising:
 a lead frame; 
 a semiconductor device; 
 a solder joint coupled between the lead frame and a terminal on the semiconductor device; 
 a reflow wall including polymer which contains particles formed of a solderable metal, and including an ink residue, the reflow wall on a portion of the lead frame and in contact with the solder joint; and 
 molding compound covering portions of the semiconductor device, the lead frame, the solder joint, and the reflow wall. 
 
     
     
       2. The packaged semiconductor device of  claim 1 , in which the reflow wall includes a closed shape. 
     
     
       3. The packaged semiconductor device of  claim 1 , in which the reflow wall surrounds the solder joint within a height of the reflow wall. 
     
     
       4. The packaged semiconductor device of  claim 3 , in which the height of the reflow wall is less than a height of the solder joint. 
     
     
       5. The packaged semiconductor device of  claim 1 , in which polymer selected from the group consisting of polyimide, epoxy, and polyester. 
     
     
       6. The packaged semiconductor device of  claim 1 , in which the reflow wall includes one of a circular, rectangular, oval, octagonal and square shapes from a top view of the packaged semiconductor device. 
     
     
       7. The packaged semiconductor device of  claim 1 , in which the packaged semiconductor device is a flip chip on lead (FCOL) package. 
     
     
       8. The packaged semiconductor device of  claim 1 , in which the reflow wall surrounds the solder joint on at least two opposing sides of the solder joint. 
     
     
       9. The packaged semiconductor device of  claim 1 , in which the reflow wall completely surrounds the solder joint. 
     
     
       10. The packaged semiconductor device of  claim 1 , comprising a printed circuit board solder pad on a bottom side of the packaged semiconductor device. 
     
     
       11. The packaged semiconductor device of  claim 10 , in which the printed circuit board solder pad is solder paste. 
     
     
       12. The packaged semiconductor device of  claim 10 , in which the printed circuit board solder pad is a solder paste containing solderable particles formed of metal selected from the group consisting of silver, copper, nickel, palladium, platinum, tin, gold and alloys thereof. 
     
     
       13. The packaged semiconductor device of  claim 12 , in which the solderable particles are dispersed throughout the solder paste. 
     
     
       14. The packaged semiconductor device of  claim 1  further comprising metallic post coupled between the solder joint and the terminal. 
     
     
       15. The packaged semiconductor device of  claim 1  further comprising a nonmetallic particle roughened surface on a portion of a surface of the lead frame surrounding the reflow wall. 
     
     
       16. The packaged semiconductor device of  claim 1 , in which the solderable metal is copper, silver, gold, platinum, nickel, palladium, brass, or alloys thereof. 
     
     
       17. A packaged semiconductor device comprising:
 a lead frame; 
 a semiconductor device; 
 a solder pad including an ink residue on a portion of the lead frame; 
 a solder joint coupled between the solder pad and a terminal on the semiconductor device; 
 a reflow wall including polymer which contains particles, on a portion of the lead frame and in contact with the solder joint and the solder pad; and 
 molding compound covering portions of the semiconductor device, the lead frame, the solder joint, and the reflow wall. 
 
     
     
       18. The packaged semiconductor device of  claim 17 , in which the solder pad is composed of particles dispersed in solder flux. 
     
     
       19. The packaged semiconductor device of  claim 17 , in which the reflow wall includes sidewalls, in which two adjacent sidewalls of the sidewalls are substantially at right angles with each other. 
     
     
       20. The packaged semiconductor device of  claim 17 , in which polymer selected from the group consisting of polyimide, epoxy, and polyester. 
     
     
       21. The packaged semiconductor device of  claim 17 , in which the packaged semiconductor device is a flip chip on lead (FCOL) package. 
     
     
       22. The packaged semiconductor device of  claim 17 , in which the particles of the polymer of the reflow wall are formed of a solderable metal. 
     
     
       23. The packaged semiconductor device of  claim 22  further comprising a nonmetallic particle roughened surface on a portion of a surface of the lead frame surrounding the reflow wall. 
     
     
       24. The packaged semiconductor device of  claim 22 , in which the solderable metal is copper, silver, gold, platinum, nickel, palladium, brass, or alloys thereof.